The present invention relates to rollers, especially to rollers whose length greatly exceeds their diameter, which can be used in apparatus for wet treatment of strip material, such as photographic roll film or prints. The invention also relates to a method of making such rollers.
In many types of apparatus for wet treatment of photographic films or the like, a web or sheet is transported along one or more straight and/or U-shaped paths by means of a conveyor system employing a number of rollers whose ends are provided with shafts or analogous mounting or coupling means for convenient installation in the frame. The rollers are disposed singly or in pairs and are normally provided with smooth external surfaces to reduce the likelihood of damage to the photosensitive emulsion. The surface finish and the material of the rollers depend on the nature of fluids which act upon the rollers during treatment of the processed material. For example, rollers which are presently used in developing tanks for photographic material comprise cores consisting of high-quality steel and coats of rubber. Other materials are used for those rollers which transport the film in a fixing or rinsing tank. The rollers at the drying station normally comprise a stainless core surrounded by a coating of phenolic resin. In many instances, the entire roller consists of high-quality steel. The manufacturing cost of such a large variety of rollers for use in a combined developing, fixing, rinsing and drying apparatus is extremely high, especially since the rollers must be produced in small numbers. Moreover, an unskilled workman is likely to confuse the rollers during assembly so that a roller which can stand the action of media in a fixing tank but is installed in the developing tank, or vice versa, is likely to be destroyed after a relatively short period of use. This can lead to prolonged interruptions in operation and substantial losses in output.